Detonation suppression helmholtz resonators for internal combustion engines



Aug 28, 1956 A G. BOBINE, JR 2,760,473

DETONATION SUPPESSION HELMHOLTZ RESONATORS FOR INTERNAL COMBUSTION ENGINES Original Filed Ju ly 2, 195] JNVENTOR Ami/2T @50pm/Lk Arrow/fx United States Patent DETONATION SUPPRESSION HELll/HOLTZ RESO- NATGRS FOR INTERNAL COMBUSTION EN- GINES Albert G. Berline, Jr., Van Nuys, Calif.

Qriginal application July 2, 1951, Serial No. 234,688, now

Patent No. 2,573,536, dated October 30, 1951. Divided and application Gctober 24, 1951, Serial No. 252,818, new Patent No. 2,738,781, dated March 20, 1956. Divided and application December 6, 1955, Serial No. 551,253. Again divided and this application April 16, 1956, Serial No. 578,476

2 Claims. (Cl. 12S-191) This invention relates generally to internal combustion engines and to means for suppressing irregular burning and detonation of fuel-air mixture therein. The invention is based on my discovery, that detonation in combustion engines involves acoustic phenomena and can be alleviated by means of certain acoustic apparatus used in combination with the combustion chamber.

The present application is a division of my copending application Ser. No. 551,263, tiled December 6, 1955, allowed February 15, 1956, entitled Piston Carried Detonation Suppression Means for Internal Combustion Engines. That parent application was in turn a division of my application Ser. No. 252,818, iiled October 24, 1951, entitled Engine Detonation Control by Acoustic Methods and Apparatus, now Patent No. 2,738,781, which application was a division of my earlier application Ser. No. 234,688, filed July 2, 1951, entitled Engine Detonation Control by Acoustic Methods and Apparatus, now Patent No. 2,573,536.

The present invention is based on'the fact that detonation in an engine combustion chamber produces sound waves, a large part of which rise to high amplitude at resonant frequencies of the chamber, and on my discovery that the sound waves produce the various wellknown and harmful manifestations of detonation. According to my basic invention, I inhibit or attenuate these harmful effects by interfering with or attenuating the high amplitude detonation-induced sound waves, and this is done by use in connection with the combustion chamber of acoustic attenuation means made responsive to the frequencies at which the detonation induced sound waves build up to high amplitudes.

A general object of the invention is the provision of simple and eective acoustic attenuator means for the combustion chambers of internal combustion engines, particularly, if not necessarily, adapted for incorporation in the head of the piston of the engine, and characterized by effectiveness, simplicity, low cost, and freedom from carbon accumulation.

The invention will be best understood by referring immediately to the following detailed description of one illustrative embodiment thereof, reference being had to the accompanying drawings, in which:

Fig. 1 is a vertical transverse section through an internal combustion engine showing the sound wave attenuators of the engine in elevation;

Fig. 2 is a vertical medial section through the piston of the engine of Fig. 1, and showing the attenuators also in vertical medial section.

In the drawings, there is shown an illustrative L-head engine comprised of a Water-cooled block 10, a watermore or less conventional cooling jackets and head 11 has an inner combustion chamber-wall 20 enclosing a combustion chamber space 21 over the cylinder and valves, as shown.

The head or top wall of the piston is formed with cylindrical sockets 27 to receive Helmholtz resonators 28. These resonators, which may be of different size for this frequency response, each have a cylindrical body 29, rounded at the bottom, and formed at the upper end with an external annular liange 30 which snugly lits in the socket 27, the body 29 being annularly spaced from the piston structure excepting at flange 30 and at its lower end, as shown. Heat conduction to the piston structure is thus reduced, and the resonator operates at a relatively high temperature. 29 is provided with a stem 32 extending down through the head of the piston, its lower end being riveted as at 33, to secure the resonator tightly in position.) The resonator includes top wall 34, having downwardly extending tubular stem 35 which opens into the lower portion of body 29, this stem being thus the neck of the resonator. The farthest inner end portion of the cavity of this resonator, where any carbon might tend otherwise to accumulate, will be seen to be the part which is turned toward the heat to give a condition of temperature substantially above the range wherein carbon will deposit, with the result that carbon accumulation within the resonator is minimized or prevented. Y

The effectiveness of Helmholtz resonators coupled into the combustion chamber of. an internal combustion engine and tuned to those frequencies at which detonation tends to occur has been fully set forth in my aforementioned Patent No. 2,573,536, and need not be repeated herein.

It will be understood that the drawings and description are merely illustrative of one specific embodiment of the invention, and that various changes in design, structure and arrangement may be made without departing from the spirit and scope of the appended claims.

l claim:

l. For use with an internal combustion engine having a combustion chamber and a cylinder opening into said chamber, a piston adapted for reciprocation in said cylinder, said piston having a recess sunk into its top wall, and a resonator mounted in said recess, said resonator comprising a hollow body mounted in said recess, with its Wall surfaces in limited contact with the walls of said recess, and an elongated tubular neck extending downwardly into said resonator from its top to provide communication between said chamber and the bottom region of said resonator. t

2. For use with an internal combustion engine having t No references cited.

At the bottom, body 

